Liquid crystal display device and method of fabricating the same

ABSTRACT

A liquid crystal display device includes a plurality of gate lines and data lines crossing each other to define a plurality of pixel regions, a plurality of thin film transistors, each disposed in one of the pixel regions, and a plurality of pixel electrodes, each disposed in one of the pixel regions, wherein the thin film transistor includes at least one Ti layer.

This is a is a divisional of U.S. patent application Ser. No.12/453,050, filed Apr. 28, 2009, now U.S. Pat. No. 7,824,940 which is adivisional of U.S. patent application Ser. No. 10/664,931, filed Sep.22, 2003, now U.S. Pat. No. 7,532,267 both of which are herebyincorporated by reference. The present invention claims the benefit ofKorean Patent Application No. 88430/2002 filed in Korea on Dec. 31,2002, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device and method offabricating a display device, and more particularly, to a liquid crystaldisplay device and a method of fabricating a liquid crystal displaydevice.

2. Description of the Related Art

In flat panel display devices having active devices, such as a liquidcrystal display (LCD) devices, thin film transistors (TFTs) are disposedin each pixel region to drive pixel cells in the display device. Adriving method using the TFTs is commonly referred to as an activematrix driving method, wherein the active devices are placed within eachpixel region and are arranged in a matrix configuration to drive theindividual pixel cells.

FIG. 1 is a plan view of an LCD device according to the related art. InFIG. 1, an LCD device includes an N×M-number of pixels arranged alongvertical and horizontal directions, wherein each pixel includes a TFT 10formed at crossing regions of a gate line 3, which receives a scansignal from an external driving circuit, and a data line 5, whichreceives an image signal. The TFT 10 includes a gate electrode 11connected to the gate line 3, a semiconductor layer 12 formed on thegate electrode 11 to be activated by a scan signal supplied to the gateelectrode 11, and source and drain electrodes 13 and 14 formed on thesemiconductor layer 12. In addition, a pixel electrode 16 is formedwithin a display region of the pixel and is connected to the drainelectrode 14 to drive liquid crystal molecules according to theactivation of the semiconductor layer 12.

FIG. 2 is a cross sectional view along I-I′ of FIG. 1 according to therelated art. In FIG. 2, the TFT 10 is formed on a first substrate 20made of a transparent material, such as a glass, and includes the gateelectrode 11 formed on the first substrate 20, a gate insulating layer22 deposited over the first substrate 20, the semiconductor layer 12formed on the gate insulating layer 22, the source and drain electrodes13 and 14 formed on the semiconductor layer 12, and a passivation layer24 disposed over an entire area of the first substrate 20. In addition,a pixel electrode 16 is formed on the passivation layer 24 and isconnected to the drain electrode 14 through a contact hole 26.

In FIG. 2, a black matrix 32 and a color filter layer 34 are formed on asecond substrate made of a transparent material, such as glass. Theblack matrix 32 is formed in a non-display region, such as the TFTforming region, and in a region between pixels to block lighttransmission in the non-display region. In addition, the color filterlayer 34 includes red (R), green (G), and blue (B) layers formed on thesecond substrate 30, wherein the first and second substrates 20 and 30are bonded together with a liquid crystal material layer 40 formedtherebetween.

FIGS. 3A-3I are cross sectional views of a method of fabricating an LCDdevice according to the related art. In FIG. 3A, a metal layer 11 a isdeposited on a first substrate 20 (i.e., TFT substrate), and aphotoresist layer 60 a is deposited on the metal layer 11 a, wherein thedeposited photoresist layer 60 a is then baked at a certain temperature.Next, a mask 70 is positioned above the baked photoresist layer 60 a,and light, such as ultraviolet light, is irradiated onto the photoresistlayer 60 a.

In FIG. 3B, a developer is applied to the photoresist layer 60 a,thereby forming a photoresist pattern 60 on the metal layer 11 a.Accordingly, since the photoresist is a negative photoresist, regionsthat are not affected by the ultraviolet light are removed by thedeveloper.

In FIG. 3C, a portion of the metal layer 11 a covered by the photoresistpattern 60, is removed by applying an etchant to the metal layer 11 a.Accordingly, a gate electrode 11 is formed on the first substrate 20.

In FIG. 3D, a gate insulating layer 22 is formed over the firstsubstrate 20 and a semiconductor layer 12 a is formed thereon. Then, aphotoresist layer is deposited on the semiconductor layer 12 a andultraviolet light is irradiated onto the photoresist layer using a mask.Next, a developer is applied to portions of the photoresist layer thatmay been irradiated with the ultraviolet light to form a photoresistpattern 62 on the semiconductor layer 12 a.

In FIG. 3E, an etchant is applied to the semiconductor layer 12 a usingthe photoresist pattern 62 as an etch-blocking mask to form asemiconductor layer 12 on the insulating layer 22.

In FIG. 3F, a metal layer (not shown) is deposited on an entire surfaceof the first substrate 20, and a photoresist pattern (not shown) isformed on the metal layer using a mask. Then, the metal layer is etchedusing the photoresist pattern as an etch-blocking mask to form sourceand drain electrodes 13 and 14 on the semiconductor layer 12.

In FIG. 3G, a passivation layer 24 is deposited on the first substrate20 including the source and drain source electrodes 13 and 14. Then, aportion of the passivation layer 24 formed on the drain electrode 14 isetched using the photolithographic processes described above, therebyforming a contact hole 26 exposing a portion of the drain electrode 14.

In FIG. 3H, a transparent material, such as indium tin oxide (ITO), isdeposited on the passivation layer 24 and etched using theabove-described photolithographic processes to form a pixel electrode 16on the passivation layer 24. In addition, the pixel electrode 16 iselectrically connected to the drain electrode 14 via the contact hole 26formed in the passivation layer 24.

In FIG. 3I, a black matrix 32 and a color filter layer 34 are formed ona second substrate 30 (i.e., color filter substrate), and the first andsecond substrates 20 and 30 are bonded together with a liquid crystalmaterial layer 40 sandwiched therebetween.

Accordingly, as described above, the source and drain electrodes 13 and14 and the semiconductor layer 12 are formed using photolithographicprocesses including the photoresist layers. However, using thephotoresist layers is problematic. For example, the photolithographicprocesses are complicated since the photoresist patterns are formedthrough repeated processing including photoresist depositing, baking,irradiating, and developing. In addition, the baking process actuallyincludes a soft baking process and a hard baking process that areperformed at separate temperatures.

Moreover, since the fabrication processes include forming of a pluralityof patterns (or electrodes), a plurality of photoresist processes arerequired. Accordingly, since photoresist processing must be performed tocreate each of the patterned lines, fabrication costs increase. Forexample, the fabrication costs of the photoresist process areapproximately 40-45% of a total cost of the TFT substrate process.

Furthermore, the fabrication processes generate significant amounts ofenvironment contaminants. In general, since the photoresist layer isformed by deposited photoresist material using a spin coating method,most of the photoresist material may be discarded. Accordingly, thediscarded photoresist material increases fabrication costs of the TFTsubstrate and introduces contaminants into the environment.

In addition, performance of the LCD device may degrade due to remnantamounts of the photoresist material. For example, since the photoresistmaterial is coated using the spin coating method, it is difficult tocontrol a thickness of the photoresist layer. Accordingly, thephotoresist layer has a non-uniform thickness and portions of thephotoresist layer may remain after the photoresist pattern is supposedto be completed removed.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a liquid crystaldisplay device and a method of fabricating a liquid crystal displaydevice that substantially obviates one or more of the problems due tolimitations and disadvantages of the related art.

An object of the present invention is to provide a liquid crystaldisplay device that includes a TiN layer formed during fabrication.

Another object of the present invention to provide a method offabricating a liquid crystal display device having simplifiedfabrication processes and reduced fabrication costs.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, a liquidcrystal display device includes a plurality of gate lines and data linescrossing each other to define a plurality of pixel regions, a pluralityof thin film transistors, each disposed in one of the pixel regions, anda plurality of pixel electrodes, each disposed in one of the pixelregions, wherein the thin film transistor includes at least one Tilayer.

In another aspect, a liquid crystal display device includes a pluralityof gate lines and data lines cross each other to define a plurality ofpixel regions, a thin film transistor in each pixel region, a pixelelectrode in each pixel region, and a metal masking layer in the thinfilm transistor.

In another aspect, a method of fabricating a liquid crystal displaydevice includes providing a first substrate, forming a gate electrode ona first substrate, forming a gate insulating layer on an entire surfaceof the first substrate including the gate electrode, forming asemiconductor layer on the gate insulating layer, forming source/drainelectrodes on the semiconductor layer, forming a passivation layer onthe gate insulating layer and the source/drain electrodes, and forming apixel electrode on the passivation layer, wherein at least one of thegate electrode, semiconductor layer, source/drain electrodes, and pixelelectrode is formed using a Ti layer and a TiN layer.

In another aspect, a method of fabricating a liquid crystal displaydevice includes forming a gate electrode on a first substrate, forming agate insulating layer on an entire surface of the first substrate,forming a semiconductor layer on the gate insulating layer, formingsource/drain electrodes on the semiconductor layer, forming apassivation layer on the source/drain electrodes, and forming a pixelelectrode on the passivation layer, wherein at least one of the gateelectrode, semiconductor layer, source/drain electrodes, and pixelelectrode is formed using a Ti masking layer and Ti pattern.

In another aspect, a patterning method includes forming an etchingsubject layer on a substrate, forming a Ti layer on the etching subjectlayer, irradiating light onto the Ti layer using a mask to form a TiNlayer, etching the TiN layer to form a Ti pattern layer, etching theetching subject layer using the Ti pattern layer, and removing the Tipattern layer.

It is to be understood that both the foregoing general description andthe following detail description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIG. 1 is a plan view of an LCD device according to the related art;

FIG. 2 is a cross sectional view along I-I′ of FIG. 1 according to therelated art;

FIGS. 3A-3I are cross sectional views of a method of fabricating an LCDdevice according to the related art;

FIGS. 4A-4F are cross sectional views of an exemplary patterning methodfor an LCD device according to the present invention;

FIGS. 5A-5F are cross sectional views of another exemplary patterningmethod for an LCD device according to the present invention;

FIGS. 6A-6J are cross sectional views of an exemplary method offabricating an LCD device according to the present invention;

FIG. 7 is a cross sectional view of an exemplary LCD device according tothe present invention; and

FIGS. 8A-8E are cross sectional views of another exemplary method offabricating an LCD device according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

FIGS. 4A-4F are cross sectional views of an exemplary patterning methodfor an LCD device according to the present invention. In FIG. 4A, ametal layer 103 may be formed on a substrate 101 made of an insulatingmaterial, such as glass or semiconductor materials, and a Ti layer 110may be formed on the metal layer 103 by evaporating or sputteringprocesses, for example.

In FIG. 4B, regions of the metal layer 103 that will be used to form ametal pattern may be blocked using a mask 107, and light, such asultraviolet or laser light, may be irradiated onto unblocked portions ofthe Ti layer 110. Accordingly, the light may be irradiated within anitrogen atmosphere, wherein the portions of the Ti layer 110 that havebeen irradiated with light may be converted into TiN during anitrification process. Initially, the nitrification process begins froman upper surface of the Ti layer 110 that receives the light, whereby anentire thickness of the Ti layer 110 eventually is converted into TiN.

In FIG. 4C, a Ti layer 110 b may be formed in the region where the metalpattern is be formed, and a TiN layer 110 a may be formed in the regionswhere the metal layer 103 is to be subsequently etched.

In FIG. 4D, the Ti layer 110 b may be patterned by removing the TiNlayer 110 a using a dry etching process. During the dry etching process,an etching rate of TiN to Cl₂ gas is faster than an etching rate of Ti,wherein Cl₂ gas or a Cl₂ mixed gas may be used as the etching gas.

In FIG. 4E, portions of the metal layer 103 may be removed using wet ordry etching processes, wherein the portion of the metal layer 103blocked with the Ti pattern 110 b may remain on the surface of thesubstrate 101.

In FIG. 4F, the Ti pattern 110 b may be remove by an etching process.During the wet etching process, since HF reacts with Ti to form TiF,which may be removed, and SO₄ ions do not react with Ti, an acid, exceptfor H₂SO₄, may be used as the etchant. During the dry etching process,the Ti pattern 110 b may be removed, wherein Cl₂ or a Cl₂ mixed gas maybe used as the etching gas.

FIGS. 5A-5F are cross sectional views of another exemplary patterningmethod for an LCD device according to the present invention. In FIG. 5A,a metal layer 203 may be formed on a substrate 201 made of an insulatingmaterial, such as glass or semiconductor material, and a TiOx layer,such as TiO₂, may be deposited on the metal layer 203. The TiOx layer210 may be directly formed on the metal layer 203 by evaporating orsputtering methods. In addition, the TiOx layer 210 may be formed bydepositing a Ti layer on the metal layer 203 and oxidizing the depositedTi by supplying heat and irradiating the Ti layer with light.

In FIG. 5B, a mask 207 may be used to prevent portions of the TiOx layer210 from being exposed to light, such as ultraviolet or laser light.Accordingly, surface portions of the TiOx layer 210 may be formed tohave hydrophilic properties. For example, TiO₂ has hydrophobicproperties, but when the TiO₂ is exposed to ultraviolet or laser light,OH radicals are generated on a surface of the TiO₂ to covert the surfacefrom hydrophobic to hydrophilic. By irradiating the ultraviolet or laserlight onto the TiOx layer, a contact angle, which is commonly considereda standard for measuring wettability of a surface of a solid, graduallydecreases. Accordingly, when the ultraviolet or laser light isirradiated for a certain amount of time (i.e., 1 hour), the contactangle is approximately 0 degrees (i.e., the TiOx layer is converted tohave hydrophilic properties).

In FIG. 5C, by irradiating ultraviolet rays to the TiOx layer, the TiOxlayer is divided into a first TiOx layer 210 a having a surface 211possessing hydrophilic properties and a second TiOx layer 210 b havinghydrophobic properties. Accordingly, when an etching solution (i.e.,etchant), such as H₂SO₄ or an alkali group-based etching solution, isapplied to the first and second TiOx layers 210 a and 210 b each havingdifferent surface properties, OH radicals of the first TiOx layer 210 ahaving hydrophilic properties are combined with SO₄ ions. In other word,a surface of the first TiOx layer 210 a may be protected by the OHradicals.

In FIG. 5D, only the second TiOx layer 210 b may be removed by theetching solution so that only the first TiOx layer 210 a, which is aTiOx pattern, may remain on a surface of the metal layer 203.

In FIG. 5E, an etching solution may be used to remove portions of themetal layer 203, wherein a patterned portion 203 a of the metal layer203 under the first TiO₂ layer 210 a may remain on the surface of thesubstrate 201.

In FIG. 5F, an etching gas, such as Cl₂/N₂ or CF₄/Cl₂, may be applied tothe first TiO₂ layer 210 a to remove the first TiO₂ layer 210 a, therebyforming the patterned portion 203 a of the metal layer 203 on thesurface of the substrate 201.

FIGS. 6A-6J are cross sectional views of an exemplary method offabricating an LCD device according to the present invention. In FIG.6A, a metal, such as Al, an Al alloy, or Cu, may be deposited on a firstsubstrate 320 made of a transparent material, such as glass, to form ametal layer 311 a. Then, a Ti layer 370 a may be formed on the metallayer 311 a. Next, a mask 380 may be positioned above the Ti layer 370 aand light, such as ultraviolet rays or laser light, may be irradiated ina nitrogen environment. Accordingly, as detailed above, regions of theTi layer 370 a irradiated by the light are converted into TiN layer.

In FIG. 6B, the regions of the converted TiN layer may be removed byapplying an etching gas, such as Cl₂ gas or a Cl₂ mixed gas, whereinonly a Ti pattern 370 may remain on the surface of the metal layer 311a.

In FIG. 6C, the metal layer 311 a may be etched using a dry or wetetching process, wherein only portions of the metal layer 311 a underthe Ti pattern 370 may remain on the surface of the substrate 320.Accordingly, a gate electrode 311 and the overlying Ti pattern 370 mayremain on the first substrate 320. Although the gate electrode 311 isshown to include a single layer structure, the gate electrode 311 mayinclude a plurality of layers.

Then, a gate insulating layer 322 may be deposited over an entiresurface of the first substrate 320 using a chemical vapor deposition(CVD) process, a semiconductor layer 312 a may be deposited on the gateinsulating layer 322, and a Ti layer 372 a may be formed on thesemiconductor layer 312 a. Next, a region of the Ti layer 372 a may becovered using a mask 381 and light, such as ultraviolet rays or laserlight, may be irradiated in a nitrogen atmosphere onto other regions ofthe Ti layer 372 a not covered by the mask 381. Accordingly, the regionsof the Ti layer 372 a not covered by the mask 381 may be converted intoTiN.

In FIG. 6D, the TiN regions of the Ti layer 372 a may be removed byapplying an etching gas, such as Cl₂ gas or a Cl₂ mixed gas, whereinonly the Ti pattern 372 may remain on the surface of the semiconductorlayer 312 a.

In FIG. 6E, portions of the semiconductor layer 312 a not covered the Tipattern 372 (in FIG. 6D) may be removed to form a semiconductor layer312 on the surface of the gate insulating layer 322. Then, a metal layer313 a, such as Cr, Mo, Al, an Al alloy and Cu, may be formed on anentire surface of the first substrate 320 and a Ti layer 374 a may beformed on the metal layer 313 a. When the light is irradiated onto theTi layer 374 a, portions of the Ti layer 374 a not covered by a mask 382may be converted in TiN.

In FIG. 6F, the converted TiN may be removed using an etching gas toform a Ti pattern 374 on the surface of the metal layer 313 a.

In FIG. 6G, the metal layer 313 a may be etched using the Ti pattern 374as a masking layer and the Ti pattern 374 may be removed. Accordingly, asource electrode 313 and a drain electrode 314 may be formed on thesurface of the semiconductor layer 312. Although not shown, the sourceand drain electrodes 313 and 314 may each include a plurality of layers.Then, a passivation layer 324 may be deposited over an entire surface ofthe first substrate 320 and a Ti layer 376 a may be formed on thepassivation layer 324. Next, light may be irradiated onto the Ti layer376 a, wherein portions of the Ti layer 376 a not covered by a mask 383may be converted into TiN.

In FIG. 6H, the TiN may be removed using an etching gas to form a Tipattern 376 on the surface of the passivation layer 324.

In FIG. 6I, the passivation layer 324 may be dry-etched using the Tipattern 376 as a masking layer to form a contact hole 326, and the Tipattern 376 may be removed. Then, a transparent electrode 316 a made ofITO (indium Tin Oxide) or IZO (indium zinc oxide), for example, may beformed on the passivation layer 324 including the contact hole 326, anda Ti layer 378 a may be formed on the passivation layer 324. Next, amask 384 may be positioned above the Ti layer 378 a, and light may beirradiated onto portions of the Ti layer 378 a not covered by the mask384, thereby forming a Ti pattern (not shown) on the surface of thetransparent electrode 316 a.

In FIG. 6J, the transparent electrode 316 a may be etched using the Tipattern (not shown) and the Ti pattern may be removed. Accordingly, apixel electrode 316 may be formed on the surface of the passivationlayer 324 and may be connected to the drain electrode 314 via thecontact hole 326. In addition, a black matrix 332 and a color filterlayer 334 may be formed on a second substrate 330, and the first andsecond substrates 320 and 330 may be bonded together with a liquidcrystal material disposed therebetween.

Alternatively, the Ti masking layers of FIGS. 6A-6J may not be removedsuch that the Ti masking layers remain in the final LCD device. FIG. 7shows an exemplary LCD device that includes the Ti masking layers. Sincethe exemplary device of FIG. 7 may be fabricated by a method similar tothe method shown in FIGS. 6A-6J, descriptions of similar structures ofthe LCD device shown in FIGS. 6A-6J have been omitted.

In FIG. 7, Ti layers 470, 472 and 474 may be formed on a gate electrode411, a semiconductor layer 412, and source and drain electrodes 413 and414, respectively. Since Ti has good electrical contact characteristicsand low electrical resistance, the Ti layers 470, 472, and 474 may beremoved or may included in the LCD device. When the Ti layers 470, 472,and 474 are to be included in the LCD device, removal processes (i.e.,etching processes) of the Ti masking layers (i.e., Ti patterns) may notbe necessary, thereby simplifying the fabrication processes.

In FIG. 7, since the Ti layers 472 may remain on the semiconductor layer412 and the semiconductor layer 412 may include silicon, the Ti layers472 may react with the silicon in the semiconductor layer 412 to formTi-silicon compounds. Accordingly, since the Ti-silicon compounds havelow contact resistance, the semiconductor layer 412 may beohmically-contacted with the source and drain electrodes 413 and 414.That is, the Ti-silicon compounds may function as ohmic contact layersbetween the source and drain electrodes 413 and 414 and thesemiconductor layer 412.

In the method shown in FIGS. 6A-6J, the LCD device may be fabricatedusing only the Ti masking layers. However, the LCD device may befabricated using both the Ti masking layers and the photoresist layers.Accordingly, the Ti masking layers of the LCD device shown in FIG. 7 maybe formed on at least one of the gate electrode 411, the semiconductorlayer 412, and the source and drain electrodes 413 and 414. In addition,the Ti masking layers may also be formed on all patterned layers of theLCD device.

FIGS. 8A-8E are cross sectional views of another exemplary method offabricating an LCD device according to the present invention. In FIG.8A, a gate electrode 511 and a first Ti pattern 570 may be formed on afirst substrate 520 using a Ti masking layer and/or a photoresist layer.Then, a gate insulating layer 522 may be deposited over an entiresurface of the first substrate 520. Next, a semiconductor layer 512 andsecond Ti pattern layers 572 may be formed on the gate insulating layer522. In addition, a source electrode 513, a drain electrode 514, andthird Ti pattern layers 574 may be formed on the second Ti patternlayers 572.

Next, a passivation layer 524 may be formed on an entire surface of thefirst substrate 520 upon which the source and drain electrodes 513 and514 may be formed. Then, a TiOx layer 576 a may be formed on thepassivation layer 524, wherein light, such ultraviolet light or laserlight, may be irradiated onto surface portions of the TiOx layer 576 ausing a mask 582. Accordingly, a surface region of the TiOx layer 576 aupon which the light has not been irradiated may have hydrophobicproperties, and the surface portions 577 (in FIG. 8B) of the TiOx layer576 a upon which the light has been irradiated may have hydrophilicproperties.

In FIG. 8B, an etching solution, such as an alkali-based solution orH₂SO₄, may be applied to different surface portions of the TiOx layer.Accordingly, the unexposed surface portions of the TiOx layer having thehydrophobic properties may be removed so that only a first TiOx layerpattern 576 having the hydrophilic properties remains on the surface ofthe passivation layer 524. In addition, the surface portions 577 of theTiOx layer pattern 576 may remain on the surface of the TiOx layerpattern 576. Then, a portion of the passivation layer 524 may be etchedusing the first TiOx layer pattern 576 as an etch-blocking layer to forma contact hole 526 exposing a portion of one of the third Ti patternlayers 574 that corresponds to the drain electrode 514. Alternatively,the surface portions 577 of the first TiOx layer pattern 576 may beremoved since TiO₂ has a resistivity of 10³ Ωcm and a transitivity ofabout 85%. Accordingly, the first TiO₂ pattern 576 may not necessarilyadversely affect light transmission of the LCD device.

In FIG. 8C, a TiOx layer 578 a may be formed on the first TiOx layerpattern 576 including in the contact hole 526. Then, a transparentelectrode 516 a, such as ITO or IZO, may be deposited on an entiresurface of the first substrate 520 and the TiOx layer 578 a. Next, lightmay be irradiated onto surface portions of the transparent electrode 516a using a mask 584 to cover regions of the transparent electrode 516 acorresponding to the semiconductor layer 512. Accordingly, the surfaceportions of the transparent electrode 516 a upon which the light isirradiated may be converted to have hydrophilic properties, and thesurface of the transparent electrode 516 a upon which the light is notirradiated may have hydrophobic properties.

In FIG. 8D, the transparent electrode 516 a may be etched, wherein theexposed surfaces of the transparent electrode 516 a having thehydrophilic properties may be remove and the unexposed surfaces of thetransparent electrode 516 a having the hydrophobic properties may remainon the surface of the TiOx layer 578 a. Accordingly, only a second TiOxpattern 579 including the surface of the transparent electrode 516 ahaving the hydrophilic properties may remain.

In FIG. 8E, an etchant may be applied to the TiOx layer 578 using thesecond TiOx pattern 579 as a mask layer, wherein the unexposed portionsof the TiOx layer 578 may be removed. Accordingly, a pixel electrode maybe formed. In addition, similar to the first TiOx pattern 576, thesecond TiO₂ pattern 578 may be removed or may remain on the pixelelectrode layer 516.

A second substrate 530 may include a black matrix 532 and a color filterlayer 534, wherein the first and second substrates 520 and 530 may bebonded together with a liquid crystal material 540 disposedtherebetween.

According to the present invention, a LCD device may be formed usingpatterns formed of Ti and/or TiOx. However, the LCD device may befabricated using only Ti, both Ti and a photoresist, or both Ti andTiOx. In addition, the LCD device may be fabricated by using Ti, TiOx,and the photoresist in combination.

In addition, according to the present invention, the LCD device may befabricated with a Ti layer on at least one of the gate electrode, thesemiconductor layer, and the source electrode/drain electrode. Moreover,it is possible to form the TiOx layer on at least one of the passivationlayer and the pixel electrode, or form the TiOx layer on the gateelectrode, the semiconductor layer, and the source electrode/drainelectrode.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the LCD device and method offabricating an LCD device of the present invention without departingfrom the spirit or scope of the invention. Thus, it is intended that thepresent invention cover the modifications and variations of thisinvention provided they come within the scope of the appended claims andtheir equivalents.

1. A method of fabricating a liquid crystal display device, comprising:forming a gate electrode on a first substrate; forming a gate insulatinglayer on an entire surface of the first substrate; forming asemiconductor layer on the gate insulating layer; forming source/drainelectrodes on the semiconductor layer; forming a passivation layer onthe source/drain electrodes; and forming a pixel electrode on thepassivation layer, wherein at least one of the gate electrode,semiconductor layer, source/drain electrodes, and pixel electrode isformed by etching a conductive layer or semiconductive layer using a Timasking layer and Ti pattern, the Ti masking layer being formed bydepositing a Ti layer on the conductive layer or semiconductive layer,irradiating light to the Ti layer, and etching the expose portion of theTi layer by the etching speed different between the Ti layer and theexposed Ti layer.
 2. The method according to claim 1, wherein theforming a gate electrode comprises: forming a metal layer on the firstsubstrate; forming the Ti masking layer on the metal layer; irradiatinglight onto a portion of the Ti masking layer using a mask to convert theexposed portion of the Ti masking layer into a TiN layer; removing theTiN layer to form the first Ti pattern; and etching the metal layerusing the first Ti pattern as a mask to form the gate electrode and thefirst Ti pattern.
 3. The method according to claim 2, wherein the TiNlayer is removed using an etching gas.
 4. The method according to claim1, wherein the forming of a semiconductor layer comprises: forming thesemiconductor layer on the gate insulating layer; forming a Ti maskinglayer on the semiconductor layer; irradiating light onto a portion ofthe Ti masking layer using a mask to convert the Ti masking layer into aTiN layer; removing the TiN layer to form the Ti pattern; and etchingthe semiconductor layer using the Ti pattern as a mask to form thesemiconductor layer and the Ti pattern.
 5. The method according to claim4, wherein the TiN layer is removed using an etching gas.
 6. The methodaccording to claim 1, wherein the forming of source/drain electrodescomprises: forming a metal layer on the semiconductor layer; forming theTi masking layer on the metal layer; irradiating light onto a portion ofthe Ti masking layer using a mask to convert the exposed region of theTi masking layer into a TiN layer; removing the TiN layer to form the Tipattern; and etching the metal layer using the Ti pattern as a mask toform the source/drain electrodes and the Ti pattern.
 7. The methodaccording to claim 6, wherein the TiN layer is removed using an etchinggas.
 8. The method according to claim 1, wherein the forming of a pixelelectrode comprises: forming an indium tin oxide layer on thepassivation layer; forming the Ti masking layer on the indium tin oxidelayer; irradiating light onto a portion of the Ti masking layer using amask to convert the exposed portion of the Ti masking layer into a TiNlayer; removing the TiN layer to form the Ti pattern layer; etching thesemiconductor layer using the Ti pattern layer as a mask; and removingthe Ti pattern layer.
 9. The method according to claim 8, wherein theTiN layer is removed using an etching gas.
 10. The method according toclaim 8, wherein the Ti pattern layer is removed using an etchingsolution.
 11. The method according to claim 8, wherein the Ti patternlayer is removed using an etching gas.
 12. The method according to claim1, further comprising forming a contact hole in the passivation layer toconnect the pixel electrode to the drain electrode.
 13. The methodaccording to claim 12, wherein the forming a contact hole comprises:forming a Ti masking layer on the passivation layer; irradiating lightonto a portion of the Ti masking layer using a mask to convert theexposed portion of the Ti masking layer into a TiN layer; removing theTiN layer to form a second Ti pattern layer; and etching thesemiconductor layer using the second Ti pattern layer as a mask; andremoving the second Ti pattern layer.
 14. The method according to claim13, wherein the TiN layer is removed using an etching gas.
 15. Themethod according to claim 13, wherein the second Ti pattern layer isremoved using an etching solution.
 16. The method according to claim 13,wherein the second Ti pattern layer is removed using an etching gas. 17.The method according to claim 1, wherein the forming a pixel electrodecomprises: forming an indium tin oxide layer on the passivation layer;forming a hydrophobic TiO₂ layer on the indium tin oxide layer;irradiating light onto a portion of the hydrophobic TiO₂ layer using amask to convert the exposed portion of the hydrophobic TiO₂ layer into ahydrophilic layer; etching the hydrophobic TiO₂ layer to form a TiO₂pattern having hydrophilic properties; and etching the indium tin oxidelayer using the TiO₂ pattern to form the pixel electrode and ahydrophilic TiO₂ pattern layer.
 18. The method according to claim 17,wherein the hydrophobic TiO₂ layer is etched using an etching solutionincluding H₂SO₄.
 19. The method according to claim 17, wherein thehydrophobic TiO₂ layer is etched using an alkali based etching solution.20. The method according to claim 1, further comprising forming acontact hole in the passivation layer to expose the drain electrode. 21.The method according to claim 20, wherein the forming a contact holecomprises: forming a hydrophilic TiO₂ layer on the passivation layer;irradiating light onto the hydrophilic TiO₂ layer using a mask to form ahydrophobic TiO₂ layer; etching the hydrophobic TiO₂ layer to form afirst hydrophilic TiO₂ pattern layer; and etching the passivation layerusing the first hydrophilic TiO₂ pattern layer to form the contact holeand a second hydrophilic TiO₂ pattern layer.
 22. The method according toclaim 21, wherein the hydrophobic TiO₂ layer is etched using an etchingsolution including H₂SO₄.
 23. The method according to claim 21, whereinthe hydrophobic TiO₂ layer is etched using an alkali based etchingsolution.